1. Field of the Invention
The present invention relates to a tilt switch for controlling current through detection of the tilt of equipment.
2. Description of the Related Art
In contrast to a tumble detection switch, a tilt switch attached to a drive unit for effecting an opening/closing operation of, for example, a crossing gate or kitchen equipment is required to exhibit high switching durability associated with repeated tilting in a certain direction. Examples of such a tilt switch include a mercury switch.
FIG. 1 is a sectional view of a conventional mercury switch serving as a tilt switch.
In FIG. 1, reference numeral 1 denotes a glass container; reference numeral 2 denotes a pair of stationary electrodes fixedly attached to the glass container; and reference numeral 3 denotes mercury enclosed within the glass container 1 and adapted to establish electrical continuity between the paired stationary electrodes 2 upon tilting of the glass container 1.
Such a conventional tilt switch using mercury involves a significant environmental problem, Is subjected to severe governmental regulations, and is not suited for use with equipment handling food, such as kitchen equipment.
FIG. 2 is a sectional view of a conventional tumble-detection-type tilt switch.
In FIG. 2, reference numeral 4 denotes a conductive ball member; reference numeral 5 denotes an electrode which also serves as a housing; reference 6 denotes an electrode which also serves as a holder for holding the ball member 4 at a neutral position; and reference numeral 7 denotes an insulator for insulating the electrodes 5 and 6 from each other.
Such a tumble-detection-type tilt switch involves problems in terms of switching capacity and switching durability.
An object of the present invention is to solve the above-mentioned problems involved in the conventional tilt switch and to provide an inexpensive tilt switch of excellent durability and low environmental impact.
(1) To achieve the above object, the present invention provides a tilt switch comprising a pair of contact elements, at least one of the contact elements being formed of an elastic member; and at least one ball member which rolls along a path defined between the contact elements. The contact elements are disposed in a facing manner such that the distance therebetween as measured at one end is greater than the diameter of the ball member, whereas the distance therebetween as measured at the other end is slightly smaller than the diameter of the ball member.
Preferably, the contact elements are disposed such that free-end portions thereof approach each other, and the tilt switch further comprises a restriction wall for maintaining a predetermined distance between the free-end portions.
Preferably, each of the contact elements is formed of a wire, and the restriction wall assumes the form of a pair of recess portions or protrusions for restricting movement of free-end portions of the contact elements.
(2) To achieve the above object, the present invention further provides a tilt switch comprising a housing having a hollow portion of a substantially columnar or cubic shape; at least one rolling member disposed in such a manner as to roll substantially linearly within the hollow portion; a contact mechanism accommodation portion disposed side by side with the hollow portion; a movable contact element and a stationary contact element accommodated within the contact mechanism accommodation portion and disposed in a facing manner, each of the movable contact element and the stationary contact element being formed of a spring element; and a working member having a pivot formed thereon, the working member being disposed in such a manner as to rotate as a result of movement of the rolling member and such that a portion thereof projects into the hollow portion.
Preferably, the stationary contact element is supported at a predetermined position by a stopper portion so as to maintain a predetermined distance away from the movable contact element. Preferably, the working member is disposed in such a manner as to project into the hollow portion while forming an obtuse angle with respect to a side wall of the hollow portion.